[聲物誌]台北藝術大學

[聲物誌]台北藝術大學

台北藝術大學位於北投區學園路的山丘上,由於校園內的景觀優美,又能從高點俯瞰關渡平原,早已經成為北投關渡地區的知名景點。但還記得12月初關於台北藝術大學校園內的石碑被更名為”台北藝術公園”的新聞嗎? 由於進入校內的遊客太多,加上校方在空間管理的政策未能和學生有效溝通,使得學生以此手段抗議「校園變公園、學殿變學店」的現象。

像是大學這種需要幽靜的環境,確實很容易受到湧入的人潮、辦理的活動而影響。假日進入到台北藝術大學,其實聽到的不是甚麼書香的聲音,往往聽到的是小孩放聲大叫、大人們嬉鬧聊天的聲音。

這些到底算不算噪音呢? 我想是因人而異。

但站在台北藝術大學的草地上,我發現除了遊客的聲音之外,其實有另外更值得大家關注、但也幾乎被所有人忽略的聲音:來自都市的低頻噪音

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我走到一處較為遠離遊客的山坡上,把我手上的錄音機朝向山坡上的一處草叢,除了遠方傳來的遊客交談聲,附近一處建築偶爾傳來的施工聲音、和後方經過的車聲之外,仔細聽會發現這裡有許多高頻、清脆、細微的蟲鳴聲。

但當我站在原地,把錄音機180度轉向關渡平原,驚人的事情發生了。大度路傳來的許多車聲、喇叭聲、松山機場起降的航班,取代蟲鳴聲成為了主角。和剛剛的聲音相比,背景中的低頻噪音非常明顯,雖然分不出確切的聲源,但可想而知應該是來自於台北的都會區。

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如果不是拿著錄音機這樣仔細地聽,其實我原本也沒有發覺原來聲音的感受在不同的角度有如此大的差別。這低頻的噪音一旦被意識抓住之後,短時間內很難不去注意它的存在。看著夕陽從關渡平原緩緩降下,聽著這截然不同的聲景,不禁想像如果台北的都會區能夠更安靜點,那我們的生活壓力是不是也會少了一點?

 

Conference presentation: 21st Biennial Conference on the Biology of Marine Mammals

13-18 Dec 2015

A noisy dinner? Passive acoustic monitoring on the predator-prey interactions between Indo-Pacific humpback dolphins and croakers

Tzu-Hao Lin, Wen-Ching Lien, Chih-Kai Yang, and Lien-Siang Chou
Institute of Ecology and Evolutionary Biology, National Taiwan University

Shane Guan
Office of Protected Resources, National Marine Fisheries Service, Silver Spring, MD, USA

The spatio-temporal dynamics of prey resources have been considered as important factors for shaping the distribution and behavior of odontocetes. Indo-Pacific humpback dolphin (Sousa chinensis) is a costal species, which primary feeds on benthic croakers. It has been hypothesized that the distribution pattern and periodic occurrence of humpback dolphins are results of their prey movement. However, the interactions between humpback dolphins and croakers remain unclear. During May 2013 and November 2014, underwater sound recordings were collected in western Taiwan waters. Croaker choruses and humpback dolphin echolocation clicks were automatically detected using custom developed algorithms. Both croaker choruses and dolphin clicks were frequently detected in shallow estuarine waters during spring and summer. In addition, shorter inter-click intervals were detected with higher frequencies in these areas, indicating more likely foraging behavior. Current results suggest that the core habitats of humpback dolphins show an agreement with the areas of prominent croaker chorus. Diurnal cycle analysis showed that croaker choruses were most evident after sunset to until approximately 4 A.M. In estuarine waters, humpback dolphin clicks were most frequently detected during the nighttime, with reduced detection rates after 8 A.M. This suggests that the diurnal behavior of humpback dolphins could be associated with the calling behavior of croakers. Although whether the position of a calling croaker could be passively localized by a dolphin remains unknown, our results indicate that the foraging probability of humpback dolphins may be elevated during the nighttime chorus of croakers. Information regarding the spatio-temporal dynamics of croaker chorus can be important for the conservation management of humpback dolphins. Further details on the predator-prey interactions between humpback dolphins and croakers can be investigated by using hydrophone arrays.

Poster (pdf)